Variable speed drive



H. J. WOOD 2,940,338 VARIABLE SPEED DRIVE June 14, 1960 6 Sheets-Sheet 1Original Filed June 14, 1951 Homer I W061i,

v mmvron Illa/'09 June 14, 1960 H. J. woos; 2,940,338

VARIABLE SPEED DRIVE Original Filed June 14, 1951 6 Sheets-Sheet 2 F '1w I n Z6 Z4 27 a9 79 81 we 10925 a2 .55 if l4- M4 e h I 3 n5 L -i' g -gnb "5 I06 m IZI 1Z9 lfil I28 7 a no lZ :20 122 Home J Wood,

@ INVENTOR.

Alto/may June 14, H. J. WOOD VARIABLE SPEED DRIVE Original Filed June14. 1951 6 Sheets-Sheet 5 Hamer- J wood INVENTOR;

Ana/we June 14, 1960 H. J. WOOD VARIABLE SPEED DRIVE 6 Sheets-Sheet 4Original Filed June 14, 1951 Homer J W004 INVENTOR.

' Attorney June 14, 1960 H. J. wooD VARIABLE spasm DRIVE 6 Sheets-Sheet5 Original Filed June 14. 1951 Homer J Wood. INVENTOR.

June 14, 1960 H. J. woon VARIABLE SPEED DRIVE 6 Sheets-Sheet 6 OriginalFiled June 14, 1951 Homer Wood,

IN V EN TOR.

I Attorne United States Patent VARIABLE SPEED DRIVE Homer J. Wood,Sherman Oaks, Calif., assignor to The Garrett orporation, Los Angeles,Calif., a corporation of California Original application June 14, 1951,Ser. No. 231,600,

now Patent No. 2,659,247, dated Nov. 17, 1953. Divided and thisapplication Sept. 8, 1953, Ser. No. 378,810

2 Claims. (Cl. 747'40) My present invention relates to a unit forsupplying air in controlled quantity and includes a compressor anddriving means therefor which may be connected to a power source, such asan internal combustion airplane engine, so as to be driven thereby. Thisis a division of my copending application, Serial No. 231,600, filedJune 14, 1951, now Patent No. 2,659,247.

It is an object of the invention to provide for connection to acompressor a compact drive system having a power input shaft which isdriven at variable speed, the driving system including variable-ratiogearings or transmissions of simple and compact form, and means,responsive to outside control, for controlling the cooperativefunctioning of the variable ratio transmissions so that the compressorwill be driven at a speed or speeds which will effect predetermined airdelivery by the compressor. I

It is a further object of the invention to provide a compressor anddrive unit having a housing containing first and second variable speedtransmisions and incorporating hydraulic means for actuation and controlof these transmissions. It is an object of the invention to provide acompressor drive unit having first and second variable ratiotransmissions through which power from a variable speed power source iscarried to the compressor impeller which is to be driven at relativelyconstant speed so that air will be delivered continuously and constantlyto an aircraft space such as a cabin or other enclosure.

It is a further object of the invention to provide in this drive unit avariable ratio transmission with control means whereby its driving ratiois changed in response to change in speed of the engine to which theinput shaft of the unit is connected. V

In this variable ratio transmission there is a simple hydraulic controlwhich acts in response to change in velocity of a rotating part from onerange of rotational speed to another. p

Further objects and advantages of the invention will be brought out inthe following part of the specification wherein detailed description isonly exemplary without limiting the scope of the invention set forth inthe appended claims or limiting the range of equivalents which may beemployed within the broad meaning of the claims.

Referring to the drawings which are for illustrative purposes only:

Fig. 1 is a face view of the power input end of the compressor anddrive;

Fig. 2 is a section taken as indicated 'by the line 2-2 of Fig. 1; I

Fig. 3 is a section taken as indicated by the line 33 of Fig. 1;

Fig. 4 is a fragmentary section taken as indicated by the line 4-4 ofFig. 1;

Fig. 5 is a large sectional view taken as indicatedby, the line 5-5 ofFig. 3, to show the end view of the centrifugal control valve;

Patented June 14, 1960 ice Fig. 6 is a section taken on line 6-6 of Fig.5 through the centrifugal control valve;

Fig. 7 is a fragmentary sectional view showing to larger scale theplanetary gearing of the second variable speed transmission shown inFig. 2;

Fig. 8 is a cross-section taken as indicated by the line 8-8 of Fig. 7;and

Fig. 9 is a fragmentary sectional perspective view of the pumps shown inFig. 4.

As shown in Fig. 2, the invention includes a compressor 10 comprising animpeller 11 arranged Within a shell 12 having a diffuser ring 13 throughwhich the air from the impeller 11 passes into the air passage 14 of theshell 12. The shell 12 is mounted on the front wall member 15 of ahousing 16 which includes a transmission case 17 cooperating to providean enclosure for transmission parts of the compressor drive which willbe described hereinafter.

The impeller 11 is fixed on the projecting portion of a shaft 18 whichextends through an opening in the front wall member 15 of the housing16. A splined end 19 of a power receiving shaft 20 projects from therear wall 21 of the transmission case 17 as shown in Figs. 2 and 3. Thispower receiving shaft 20 is adapted for connection to a power sourcesuch as a variable speed internal combustion engine of an aircraft. Thepower received by the shaft 20 is carried to the shaft 18 which mountsthe impeller 11 through a first variable speed transmission 22, detailsof which are shown in Fig. 3 and a second variable speed transmission23, shown in Figs. 2, 7 and 8.

The first variable speed transmission 22 embodies automatic speedchanging means acting in response to variation in speed of the powerinput shaft 20, and the second variable speed transmission 23 iscontrolled by deviation, from a prescribed condition, of the air whichpasses through the supercharger to a space within the aircraft. Forexample, the second variable speed transmission 23 may be controlledeither by air flow or pressure.

The first variable speed transmission 22 has high and low ratios geartrains H and L arranged to be selectively driven by the power receivingshaft 20. The high ratio gear train H comprises a gear 24 arrangedco-axially of the shaft 20 and a gear 25 which is fixed on a shaft 26constituting the power input shaft of the second variable speedtransmission 23. The low ratio gear train L of the transmission 23comprises a gear 27 of smaller diameter than the gear 24 arranged todrive a gear 28 fixed on the shaft 26. The shaft 20 extends axially intoand drives a hollow shaft or quill 29 one end 30 of which is rotatablysupported by a bearing 31 supported by the front wall member 15, and theother end 32 of which is supported by a ball bearing 33 carried by abearing case 34 supported inthe opening 35 of the transmission case 17.Within the hollow shaft 29, the shaft 20 has a shank 36 which supports ahead 37 having external splines 33 arranged for driving engagement withinternal splines 39 of the hollow shaft 29. e

The gear 27 is mounted on a cylindn'c wall 40 which is rotatablysupported on the hollow shaft 29 by bearings 41 and 42. The bearings 41and 42 are arranged on opposite sides of a collar 43 which is formed onthe hollow shaft 29, and between the collar 43 and the cylindricalmember 40 there is a one-way or free-wheeling clutch 44 through whichthe hollow shaft 29 will drive the low ratio gear 27 provided the gear27 is not being otherwise driven at a speed of rotation greater than thespeed of rotation of the hollow shaft 29. The high ratio gear 24 ismounted on a cylindrical wall 45 supported for rotation upon a portionof the cylindrical wall 40 by a bearing sleeve 46 carried by thecylindrical wall 40. A fluid actuated clutch 47 is arranged to connectthe high ratio gear 24 to the hollow shaft 29 so that the high ratiogear 24' will drive the shaft 26 through the gear 25. At this time thegear 28 on the shaft 26, which gear 28 is, larger than thegear 25,

permitting the gear 27 to-rotate upon the hollow shaft. 29

ata speed. higher. than the speed of the shaft 29.

The clutch '47 comprises a shell 48which is connected to the gear 24 soas to rotate therewith. The shell'48 supports a plurality. of annularfriction plates 49 adapted 'to frictionally drive a plurality of annularfriction plates .50, the inner edges of which engage peripheralprojections 51 on a drum 52, which hub or drum 52 has a cylindrical wall53 of reduced diameter surrounding and keyed to the portion ofthe hollowshaft 29 between the bearings 33 and 41.

Within the rightward portion of the shell 48 of the clutch 47 there isan annular piston 54 having its peripheral portion 55 in slidingengagement with the cylindric wall 56 of the-shell 48,'and having itsinner annular portion 57 in sliding engagement with a portion of thecylindrical Wall 53 ofthe hub 52. When fluid pressure is applied to thecylinder space 58, the piston 54 will be forced leftwardly and, througha dished ring59, the movement of the piston 54 will be transmitted: tothe rightward friction plate. 49, thereby forcing the plates 49 and 50of the clutch 47 into pressural engagement so that the plates 50 willfrictionally drive the plates 49. The clutch 47 will now drive the gear.24; and the variable speed transmission 22 will be operating in itshighaspeed ratio. 7

It is a feature of the invention that means are provided for actuatingthe clutch only. when the power receiving shaft is rotating within alow-speed range such as' occurs when the airplane engine isidling. Theresult is, therefore, that when the speed of the shaft 29 drops toidlingrange, the drivingratio of the transmission 22 is automaticallyincreased from low-speed ratio to high-speed ratio so that the speed of.the shaft 26 will not be materially reduced as the result of thedecrease in .the speed of, the shaft 20. The front wall member 15,

Fig. 3, has an oil chamber 60'at the. innerend of the bearing 31, whichcommunicates with the open end of the hollowshaft' 29. Oil underpressure is fed through a duct 60a to'the chamber 60,.a'nd this oilflowsIeftwardly within the interior of the hollow shaft 29. L During idlingrotation of the hollow shaft.29, oil underipressure fiows outwardly fromtheintejiior of the hollow shaft-29lhrough a'valveipo'rt 61.which'commuinicates with an external groove 62in the hollow shaft.:29 and'anopening. 63 in the cylindrical wall 53 with the cylinder spac'e58, toapply transmission case 17, butthis orifice 64is not capable ofreleasing the pressure in the cylinder space 58 when the valve port 61is open.

Within the hollow shaft 29 therejis a centrifugally operated valvedevice 65which closes the port 61, when the f speed of rotation of theshaft 20 is increased above the idling range. V The valve" device 65 hasa closure member 66 adapted to swing outwardly from the position inwhich it is shown in Fig; 3, and close the valve port 61 when apredetermined speed of rotation ofthe members 20 and 66 is of arcuateform and is swung on a pin 70 carried by one side 71 of the frame 66, soas to extend across the opening 72 of the frame 67. Near the pin 70 theside 71 of the frame 67 has a laterally projecting bracket 73 to whichaleaf spring 74 is secured by means of a rivet 75 and an adjusting screw76. The other end of the spring 74'has. a. loop 77' formed thereon forengagement with a pin. 78. which projects laterally from the closuremember 66. V

The spring 74' controls the outward movement of-the closure member 66 asfollows. When the engine which drives the shaft 20 is idli g, the speedof rotation of the shaft 20 will be considerably below 1500 r.p.m., Whenthe engine is speeded up to power delivery range; the velocity of theshaft 20 will be in the range of 2000 rpm. or greater, with "the; resultthat the closuremember 66 will be swung out into a position to close theport 61,

7' shutting off the supply of. oil under pressure to the cylinderspace'58, whereupon oil pressure will bleed: out through the orifice 64.andthe clutch 47 will be released so that the gear 24 will not now bedriven and the. one.-

way clutch.4.4 will now act to drive the low ratio. gear 7 27. Theresult of thisis that the. shaft 26.. will not have its speed ofrotation'increased to the speed of rotation of. the power receivingshaft 20 whensuch latter speed is increased toa predetermined point.

As shown in Figs. 2, 7 and 8, the shaft26 comprises a small diameterstem portion 79 and a cylindrical portion .80 of materially largerdiameter. The leftward end of the stem 79 is rotatably supported by abearing sleeve 81'carried by the transmission case 17. The front orrightward endlportion of the cylindrical part 80 is to tatably supportedby a bearing sleeve 82 supported in the opening 83 in the front wallmember 15. The cylindrical portion'80' of the shaft 26 has thereinspaced ball bearings 84 which rotatably support the inwardly projectingpart of the impeller-supporting shaft 18 which is of hollow constructionand has, near the front end thereof, internal splines 85." The inner orleftward end of the cylindrical portion 80 of the shaft 26 has thereonan annular rib or hub through, which radial openings '87 are milled toreceive planet gears 88. Shafts 89 are extended across the. openings 87,in positionsparallel to the. axis of the shaft 26, sofas.- to carrysleeve bearings 90 which rotatablysupportthe planet gears 88..

A ring gear 91 isI'supported around and inengage jectingportion-of .thesleeve 82,; this hub 92 having an annular. web 93.with a peripheralportion whichextends within the ring gear-91' The ring. gear 91comprises an alloysteel ring having internal gear teeth .94extending'fromface-to-face thereoff. Theweb 9.3 is held within theringgear91 by rings '95' which extend into spaced internal grooves 96,"oniopposite sides of the peripheral portion'ofthe web 93, and'theperiphery of the web 93 113516621197 to" engage portions of the teeth 94of the ring gearj91. .The hub '92 has spur gear teeth 98 there on. Todrive the tubular shaft 18 which supports the impeller 11,; a floatingshaft 99 is provided; this shaft 99 has an end. 100 which rotates in abearing 101 carrie bylthe shaft member26, and extends throughout thegreater portion of its length within the tubular shaft 18, there beingsplines on the forward or outer end of the shaft 99 for drivingengagement with the internal splines 85 of the shaft 18 On the innerportions of the shaft 29 isreached, for example, 1500 to l600' r.p.m. AsY shownin Figs; 5 and 6, the valve device-65 comprises a U-shaped frame,67 arranged to be slipped over a portion of the shank 36 of the shaft20. frame 67 has "a key-way 68 arranged circumferentially so as toreceive akey 69 which projects inwardly from the wall .of the hollowshaft 29 as shown 3. aThe closure member 108 which receives oil from apassage 109 and discharges the same through a passage 110 to the inlet111 of a flow controlling valve 112 adapted to restrict the outflow ofoil through the discharge passage 110 of the pump 108 so that the pump108 will react against rotation of the ring gear 91, slowing this ringgear 91 so that the planet gears 88 will roll Within the ring gear 91and thereby effect forward rotation of the gear 103 which will betransmitted through the shaft 99 and the hollow shaft 18 to the impeller11.

The pump-driving gear 106 is supported by a ball bearing 113 which is inturn supported by a hub 114 attached to the inner face of the wallmember in a position confronting the rotary pump 108. From the body ofthe gear 106 a converging wall 115 extends to an internally splinedsleeve 116 which engages the splined shaft 107 of the pump 108.

The control valve 112 includes a needle valve or closure part 117supported for axial movement within the casing of the control valve by aguide 118. The outer I end 119 of the needle valve 117 confronts -athrust pin 120 supported by a housing member 121 which cooperates with asecond housing member 122 to form a diaphragm chamber traversed by adiaphragm 123 which divides the diaphragm chamber into spaces 124 and125. A compression spring 126 urges the needle valve 117 outwardly, andthis outward movement of the needle valve 117 is transmitted by thethrust pin to the center of the diaphragm 123. The space 125 has apressure port 127 for connection to a source of controlling fluidpressure through conduit means such as shown at 128, and a pressurerelief valve 129 is arranged to connect the spaces 125 and 124. Thespace 124 is adapted to be connected to the interior of the housing 16through use of a conduit 130. In the control of the operation of thevariable ratio device 23, as need for higher speed of rotation of theimpeller 11 is required, the fluid pressure transmitted through the port127 to the space 125 is increased, thereby moving the diaphragm 123leftwardly against the resistance of the spring'126, moving the needlevalve 117 leftwardly to increase the restriction of flow of oil from thepump 108 so that the pump 108 will increase its reaction againstrotation of the ring gear 91 and reduce its speed so as to thereby causethe variable speed transmission 23 to drive the impeller 11 at anincreased velocity. It will be understod that as conditions require areduction in the speed of the impeller 11, a reduction in the pressurein the chamber 125 will accomplish this result.

The oil passage 109, Fig. 2, is adapted to receive oil oil underpressure from an oil pump 131, Figs. 1 and 4. The oil passage 109comunicates through a passage 132 in the housing of the oil pump 108with an oil passage 133 formed Within the front wall member 15 of thehousing 16. The passage 133 communcates with the oil passage 60 so thatoil under pressure will be delivered to the oil chamber 59, Fig. 3, tosupply oil under pressure to the variable ratio transmission 22 toactuate and also lubricate the same. The oil passage 133 is arrangedwithin the front member 15 so as to supply oil to the second variablespeed transmission and moving parts associated therewith.

The oil pump 131, as shown in Figs. 4 and 9, is arranged internally withrespect to the casing 17, so that it may be driven by a gear 134 fromthe gear 28 which is fixed on the shaft 26 of the transmission 23. Thepump 131 is mounted on the inner face of a cover plate 135 inside-by-side relation to scavenger pump 136 which transmits oil from theinterior of the housing 16 of the device to an oil reservoir 137schematically indicated in Fig. 1.

The pump driving gear 134 is fixed on the projecting end of a shaft 138which drives gears 139 and 140 respecn'vely of the pumps 131 and 136.The gears 139 and 140 mesh respectively with gears 141 and 142 of thepumps 131 and 136. The shaft 138, therefore, serves to drive both thepumps 131 and 136 simultaneously.

The circulation of oil in this supercharger drive'is as follows: Thescavenger pump 136 has an inlet 143, Fig. 9, communicating with theinterior of the housing 16, and an outlet 144 which is connected througha duct 145 with the reservoir 137. The oil pump 131 has an inlet passage146 which communicates through a duct 147 with the oil reservoir 137,and the pump 131 has an outlet 148 which is connected to a duct 149 withthe inlet passage 109 of the pump 108, as schematically shown in Fig. 1.The outlet port 150 of the valve 112 is connected through an oil returnduct 151 with the reservoir 137 so that the oil pumped by the reactionpump 108 will be returned to the reservoir 137. It will be understoodthat in the oil circulating system described in the foregoing, customaryadjuncts such as filtering and cooling means may be employed asindicated at 152 and 153 in Fig. 1, which means, however, do not form apart of the invention disclosed and claimed herein.

1 claim:

1. In a drive for a variable speed compressor: a support; an outputmember projecting from said support for connection to the compressorwhich is to be driven; a plural speed change transmission connected tosaid output member so as to drive the same; and a plural speed changetransmission arranged to drive said first named transmission, one ofsaid transmissions comprising a first hollow shaft, the outer end ofsaid shaft being adapted for driving a rotating part, a second shaftsupported for rotation at the inner end of said hollow shaft, saidsecond shaft having a.

portion adapted to be driven and a tubular extension surrounding aportion of said hollow shaft, external bearing means mounted in saidsupport to encircle and rotatably support said tubular extensionrelative to said support, axially spaced bearing means within saidtubular extension, said hollow shaft being supported by said axiallyspaced bearing means for rotation, a floating shaft having the outer endthereof extending into said hollow shaft, said floating shaft being aloose fit within said hollow shaft, flexible drive means drivinglyconnecting the outer end of said floating shaft to said hollow shaft,the inner end of said floating shaft being rotatably supported by theinner end of said second shaft, planet gears supported by said secondshaft at the inner end of said hollow shaft, a sun gear at the inner endof said hollow shaft meshed with said planet gears, said sun gear beingconnected to said floating shaft, a ring gear rotatably supported onsaid external bearing means concentrically of said tubular extension andmeshed with said planet gears, and means connected through gearing withsaid ring gear for varying the rate of rotation of said ring gear inreverse order to the rate of rotation of said hollow shaft.

2. In a transmission the combination of: a support; a hollow shaftrotatably supported Within said support; a second shaft arranged inaxial alignment with said hollow shaft for driving said hollow shaft,said second shaft having a tubular extension surrounding and beingrotatably supported at its inner end by said hollow shaft; externalbearing means mounted in said support to encircle and rotatably supportsaid tubular extension relative to said support; internal bearing meansbetween said tubular extension and said hollow shaft, said hollow shaftbeing supported by said internal bearing means; a floating shaft havingone end thereof extending into said hollow shaft, said floating shaftbeing a loose fit Within said hollow shaft; splined flexible drive meansin said hollow shaft drivingly connecting the outer end of said one endto said hollow shaft, the other end of said floating shaft beingrotatably supported by the inner end of said second shaft; a sun gearintegral with said floating shaft and arranged between the adjacent endsof said hollow shaft and said second shaft; planet gears meshed withsaid sun gear to revolve around said sun gear, said planet gears beingrotatably supported by said second shaft at the end of said 7 8 1tubul'az' extension contiguous to saidseeondsheift; a ring 2,103,149Cutler 'D'e c. 2-1, 1937 gear rotatably. supported on saidexternalbearing means 2,212,046; Ross Aug. 20', 1940 condntfically of saidtubular extension and meshed witllg 2,289,285 7 Chilton f July 7, 1942'said planet gears; and nieans connected through gearing 2,328,291Osborne Aug. 31, 194-3 with said' ring gear for controlling the rotationof said 5 2,377,199 Adams et a1 May 29; 1945 ring gear. Y V 2,451,767Nardone Oct. 19, 1948 V V j t 1 2,559,128 McFarland July 3, 1951References Cited in the file ,of this patent. 2,583,556 Fleischel Jan.29, 1952 UNITED STATES PATENTS 625,047 f "fi -7 1953 V v r 10 2,715,834am er 'n Hg. 23, 1955 1,765,822 Bronander 1930 2 737 0 4 S ki Man 6,1956 1,961,679 Walti June 5, 1934 UNITED STATES PATENT OFFICECERTIFKCATE OF CORRECTEUN June 14 1960 Patent No. 2 940338 Homer 3 Woodears in the printed specification It is hereby certified that error appthat the said Letters of the above numbered patent requiring correctionand Patent should read as corrected below.

Column 5, line 51 strike out "oil", first occurrence; column 6, line 22strike out "variable speed" and insert the same after "a", firstoccurrence same line.

Signed and sealed this 20th day of December 1960,.

( SEA L) Attest:

KARL H. AXLINE Attesting Officer ROBERT C. WATSGN Commissioner ofPatents

